Good luck, dude! I hope it gets sorted.

 

what year evo is this? i am having your exact issue and on my TB on the back is a plate with a screw and behind that plate is a idle heat flapper i believe its called. mine fell apart in my hand, its on all 03 and 04 evo TB

 

05 evo . Gonna change out my spark plugs today, hope this is the final part to my problem.